Insulating-lining and process of making same.



.No. 718,378. PATYENTED JAN. 13, 1903.

G. B. PAINTER. f INSULATING LINING AND PROCESS OF MAKING SAME.

UNITED STATES PATENT OFFICE.

GEORGE E. PAINTER, OF SOHENEOTADY, NEW YORK, ASSIGNOR TO THE GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

INSULATING-LINING AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 718,378, dated January 13, 1903.

7 Application filed'Octoher 6, 1898. Serial No. 692,789. (No specimens.)

T0 ctZZ whom, it may concern:

Be it known that I, GEORGE E. PAINTER, a citizen of the United States,residing at Sch enectady, county of Schenectady, and State of New York, have invented certain new and useful Improvements in Insulating-Linings and Processes of Making Them, of which the following is a specification.

My invention relates to that class of electrical apparatus in which a metallic shell surrounds other metallic parts serving to carry or regulate an electric current and will be described with particular reference to sockets for incandescent lamps, though it is useful in Various other relations. In such apparatus it is highly desirable that the metallic shell should be lined with an insulating-sheet for obvious reasons. It has hitherto been the custom to stamp out from sheets of fiber or other similar material curved pieces which would when assembled form an approximately-cylindrical lining of the proper shape; but this arrangement was objectionable, both because of the cost of manufacturing and assembling such pieces and because of the imperfection of the lining thus formed.

My invention contemplates forming a single lining of the proper shape, made in one piece and entirely suitable for the purpose for which it is intended.

My invention also comprises a new process of working insulating material.

I have discovered that it is possible to work insulating material-such as fiber, hard rubber, dad-by a treatment that is not applicable to metal and to work a simple cylinder into fairly complex forms by dies suitably shaped. I therefore in the practice of my invention take tubes of insulating material, cut them to suitable lengths, and submit them to the action of dies in a manner to be explained below.

The invention will be more clearly understood from the accompanying drawings,which illustrate one of the linings suitable for lampsockets and the method of making it.

Figure 1 is a perspective view of the parts of the ontershell of the lamp-socket and the insulating-lining ready to be applied. Figs.

the lining A is made.

the cut a" may be omitted, the lining otherwise being the same. B is the cap of the socket, and O'the shell.

In Fig. 2, A is asection of tube from which This may be of any suitable fibrous or-insnlating material. I have used both hard rubber and insulating fiber made by any of the processes now well known in the art with good effect. The upper portion of the female die D makes a working fit with the tube A, and the upper part of the male die D similarly fits the inside of the tube. In practice the female die forms part of an operating-table, and the male die is vertically reciprocated by a suitable power-press. The female die D has shoulders at for guiding the lower portion of the tube inward when it is forced downwardly by the shoulder 61? of the male die D which shoulder d is curved, so that, as illustrated especially in Fig. 3, the ends of the tube when turned over in the process of manufacture will not strike at too obtuse an angle upon the die D The top of the female die is slightly countersunk, so that the tube may readily enter it. The height of the upper portion of the female die is such that it prevents the tube from buckling outwardly when the lower portion of the tube engages the shoulder (1. The height shown is sufficient to prevent the buckling of the tubes of insulating fiber generally used.

In Fig. 3 the process of manufacture is shown at a further stage. Here the dies have been pressed together and the ends ct 0f the 5 tube have begun to turn over against the shoulders d of the lowerdie. -The material flows, as shown, urged forward by the shoulder d of the male die D until it assumes successively the positions and form shown in' ICO Figs. 3, 4, and 5. In Fig. 3 the lower portion of the tube, after having been turned inwardly by the shoulder cl, is engaged by the portion D of the male die D which prevents its buckling up into the space between the two dies and draws it fart-her downward into the lower portion of the female die D and at the same time compresses the material against the wall of the latter. Fig. 4c shows a further degree of this step of the process, wherein the portions of the tube which have been subsequently turned inwardly by the shoulder d are redirected or drawn and compressed, as was the first portion. In. Fig. 5 the shoulder ofthe die D is shown as having reached its final position opposite the shoulder of the female die D, thus completing the operation upon the tube. This process of working an open-ended tube is not, as far as I am aware, known or used in metal workings,and, indeed, its operativeness depends upon the peculiar characteristics of the material used. Subsequently the notches a a 01. are cut in any desired way, usually by a milling-cutter, and the lining is complete.

It will be seen from an examination of the figures that the lower part D of the male die so nearly fits the inner bore of the lower die that the lower part of the tube A has no room to crimp or buckle, but is compressed and upset, so that the lining forms a smooth inner and outer surface. When made of fiber, this compression is considerable, and the lining is stronger and more substantial than the tube from which it is made.

The wall of the portion of the complete lining which has the smaller diameter and also the shoulder are of substantially the same thickness as the portion of larger diameter, varying therefrom by only afew thousandths of an inch. The wall of the smaller portion is of a uniform degree of compression, which gradually decreases along the shoulder,whereas the wall of the larger portion is unchanged in thickness and density. The character of the finish of the surface of the compressed portion of the completed tube is dependent upon the conditions of the unworked tube. Usually the smaller portion will be uniformly compressed, so as to have a perfectly smooth surface; but sometimes it will crimp or buckle longitudinally, these crimped portions being immediately compressed, so that the surface has a roughened appearance. If the material of which the unworked tube is composed is not of sufiicient rigidity, it is first shown in working by a circumferential bucklearound the top of the tube beneath the shoulder of the die D It will be obvious that my invention is not limited to use in connection with a circular tube or to the production of a lining of the form shown.

What I claim as new, and desire to secure by Letters Patent of the United States, is-

1. A lining for lamp-sockets which consists of a single piece of insulating sheet-fiber shaped by molding to have a shoulder intermediate its length and with the sections on opposite sides of said shoulder of different diameters.

2. A lining for lamp-sockets which consists of a single piece of insulating fiber shaped by molding into a tube having cylindrical portions of different diameters and a shoulder portion joining the other portions.

3. As a new article of manufacture, a lining for the socket of an incandescent electric lamp, consisting of a removable integral sheath ofinsulating material shaped to fit the inside of a shell, having two different inside diameters, said lining having the slots a a through which the securing-screws may pass.

4.. As a new article of manufacture, a lining for the socket of an incandescent electric lamp, consisting of a removable integral sheath of insulating material shaped to fit the inside of a shell, having two different inside diameters, said lining having slots d d for the screws, and the slot a for the key of the socket.

5. The process described of makinginsulating-linings, which consistsin forminginsulating fiberintoa tube, and then forcing the cold tube into a die and upsettinga part of it to a less diameter,so that the fiberis caused to flow.

6. The process of makingan insulating-lining, which consists in upsetting the end of an open tube of insulating material to a smaller diameter, and confining the end while being upset between relatively moving surfaces so that crimping or buckling is prevented.

7. The process of making an insulating-lining, which consists in radially compressing a portion of an open tube of insulating fiber by longitudinally-exerted pressure and confining the portion under compression between relatively moving surfaces.

8. The method of manufacture which consists in molding a tube of insulating material of substantially the character described of uniform diameter into a tube of different diameters by mechanical pressure, whereby the material is caused to flow.

9. The method of manufacture which consists in compressing one portion of a tube of insulating material of substantially the character described in such manner that the material is caused to flow and the diameter of that portion is reduced, while maintaining constant the dimensions of the other portion.

10. The method of manufacture which consists in compressing one portion of a tube of insulating material of substantially the character described in such manner that the material is caused to flow and the diameter of that portion is reduced, while the diameter of the other portion, and the thickness of material of the entire tube, are maintained constant.

11. The method of manufacture, which consists in forcing a tube of insulating material of substantially the character described into a space of less diameter than the tube, but of ICO sis ers substantially the same thickness as that of the material of the tube, whereby the material is caused to flow, the thickness of the tube is kept constant, but its diameter is decreased.

12. The method of manufacture which consists in forcing a tube of insulating material of substantially the character described into a space of less diameter than the tube, but of substantially the same thickness as that of the material of the tube, whereby the material is caused to flow, and preventing longitudinal expansion of said material.

13. The method of manufacture, which consists in forcing the end of a tube of insulating material to turn inwardly, and then redirecting such portion and continuing to do so while forcing continuous portions of the tube to follow the inwardly-turning movement of the end thereof, which portions are in turn redirected to cause them to assume the desired shape.

14. The method of manufacture, which consists in forcing the end of a tube of insulating material to turn inwardly and then redirecting and compressing such portion and continuing to do so while forcing continuous portions of the tube to follow the inwardlyturning movement of the end thereof, which portions are in turn redirected to cause them to assume the desired shape.

15. Aliningofinsulatingmaterialforlampsockets, which consists of a tube, one portion being of larger diameter than the other, the shoulder or bend between the two portions and also the portion of smaller diameter being shaped by molding, whereby the lining is adapted to fit the interior of the shell of the socket.

16. As a new article of manufacture, alining for shells of lamp-sockets, said lining being molded from a tube of moldable insulating material, and having a suitable shape for fitting the usual interior shoulder which is located as well known, about midway the length of the shell.

1'7. As a new article of manufacture, alining of moldable insulating material for lampsockets, said lining being in the form of atube, one end of which is of smaller diameter and greater degree of compresslon than the other end.

18. A lining of moldable insulating material for the metallic shell of lamp-sockets, being a tube, one portion of the tube being of larger diameter than the other, and a curved shoulder being formed at the jointure of said portions, the portion of a largerdiameter being adapted to fit the wider half of the metallic shell, the other portion being adapted to fit the other half of the shell, and a curved shoulder being adapted to fit the curved shoulder between the wider and narrower halves of the shell,which shoulder islocated as usual, about midway the length of the shell.

19. A lining of insulating material for lampsockets, being a tube of uniform thickness of material, and one portion of the tube being of larger diameter than the other, whereby the lining is adapted to fit the wider and narrower halves of the metallic shell of the socket.

20. A lining for lamp-sockets, said lining being made from a tube of moldable insulating material, and being in the form of a tube of two different diameters, with a curved shoulder at the jointure of the portions of different diameters, whereby the lining is adapted to fit the wider and narrower halves of the metallic shell of the socket, and also the curved shoulder between such halves.

21. The method of manufacture of linings for lamp-sockets, which consists in subjecting fibrous insulating material of sheet thickness to compression strains between dies adapted to cause the material to flow into a desirable shape.

22. The method of manufacture, which consists in subjecting a tube of suitable insulating material of substantially the character described to compression strains between dies designed to cause the material to flow to assume the shape of a tube of less diameter.

23. An insulating-sleeve forincandescentlamp sockets consisting of a seamless tube of insulating fiber having cylindrical end portions of difierent diameters.

24. An insulating-lining for the shells of incandescentdamp sockets consisting of insulating fiber having cylindrical end portions of different diameters.

In witness whereof I have hereunto set my hand this 3d day of October, 1898.

GEORGE E. PAINTER.

Witnesses:

B. B. HULL, O. L. HAYNES. 

